Effect of <Emphasis Type="Italic">Lactobacillus acidophilus</Emphasis> Bauer and <Emphasis Type="Italic">Bifidobacterium animalis</Emphasis> ssp. <Emphasis Type="Italic">lactis</Emphasis> BB12 on proteolytic changes in dry-cured loins

The effect of the potentially probiotic bacteria strain of Lactobacillus acidophilus Bauer and probiotic bacteria Bifidobacterium animalis ssp. lactis BB12 on proteolytic changes of proteins in dry-cured loins during fermentation and cold storage was studied. Results of the conducted tests demonstrated that the use of probiotic bacteria for the production of dry-cured meats impacts the generation of products of protein proteolysis with high antioxidant activity. The highest antioxidant activity of peptides after fermentation and cold storage was observed in the loin with the strain B. animalis ssp. lactis BB12 and the loin with the mixture of strains L. acidophilus Bauer and B. animalis ssp. lactis BB12. Qualitative analysis of peptides demonstrated that peptides with weight below 3.5 kDa are characterized by the highest capacity of quenching the ABTS cation radical, including the peptides in loins with the strain B. animalis ssp. lactis BB12.     

Antioxidative Effect of Seaweed Extracts in Chilled Storage of Minced Atlantic Mackerel (<Emphasis Type="Italic">Scomber scombrus</Emphasis>): Effect on Lipid and Protein Oxidation

In this study, antioxidant activity of absolute ethanol, 50 % ethanol and water extracts of two species of seaweeds namely, Fucus serratus and Polysiphonia fucoides were evaluated for their ability to retard lipid and protein oxidation in minced mackerel. Mackerel mince added with 0.5 g/kg of extracts was prepared. For comparison, BHT at 0.2 g/kg and a control with no added extracts were also prepared. The samples were stored at 5 °C for 8 days, and sampling was done at time 0, 1, 2, 4, 5 and 8 days. The 50 % ethanolic extracts of P. fucoides were found to be very effective in retarding lipid and protein oxidation, as it resulted in low levels of peroxide value, volatiles and carbonyl compounds and protected against the loss of α-tocopherol and tryptophan residues. In spite of the higher phenolic content, the absolute ethanol extracts of both species showed a pro-oxidative tendency in minced mackerel. Water extract with lowest phenolic content showed no antioxidant effect in minced mackerel. In conclusion, the 50 % ethanolic extracts of P. fucoides can be a potential source of natural antioxidants, as these extracts have antioxidant activities similar to synthetic antioxidants such as BHT. However, the extent of protection offered by these extracts against protein oxidation was not clear and further studies are needed to understand the nature of the interaction between proteins and these extracts.     

A Novel Functional Wrapping Design by Complexation of ε-Polylysine with Liposomes Entrapping Bioactive Peptides

An innovative edible wrapping with potential use for designing functional foods with antimicrobial capacity was developed by complexation of ε-polylysine with peptide-loaded liposomes. Unmarketable long-term frozen cooked shrimp (Litopenaeus vannamei) muscle was used as a source of both bioactive peptides and complex liposomal suspension carrier, producing a sustainable value-added protein wrapping material with desirable sensory properties. A <10-kDa peptide fraction (SH) with antioxidant and angiotensin-converting enzyme inhibitory capacity was encapsulated in partially purified phosphatidylcholine (PC) liposomes (LSH) with an entrapment efficiency of 85 %. The average size and zeta potential of LSH were 164?±?2 nm and –37.0?±?1.7 mV, respectively. The LSH surface changed from electronegative to electropositive upon adsorption of ε-polylysine (PL) with an optimal concentration of 0.5 %. The average diameter and zeta potential of the resulting complex ε-polylysine-adsorbed liposomes containing the peptide hydrolysate (PL-LSH) were 216?±?5 nm and +51.1?±?1.1 mV, respectively. The ε-PL proved to be effective as liposome stabilizing and antimicrobial agent. The PL-LSH suspension was incorporated in the formulation of the protein wrapping to provide it with both bioactive and antimicrobial properties. The wrapping showed low water solubility (≈30 %) and low mechanical resistance (tensile strength?=?0.23?±?0.06 MPa; elongation at break?=?0.91?±?0.19 %) properties that allowed it to be very versatile for varied food design and was effective against Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Yersinia enterocolitica.     

Antioxidant and emulsion properties of freshwater carps (<Emphasis Type="Italic">Catla catla</Emphasis>, <Emphasis Type="Italic">Labeo rohita</Emphasis>, <Emphasis Type="Italic">Cirrhinus mrigala</Emphasis>) protein hydrolysates prepared using flavorzyme

Fish protein hydrolysates (FPHs) were prepared from freshwater carps (Catla catla, Labeo rohita, and Cirrhinus mrigala) using flavorzyme at different degrees of hydrolysis (DHs) ranging from 5 to 20%. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical-scavenging activity of the FPHs prepared from the three species were in the range of 50–82%; the ferric reducing power of the FPHs prepared from catla was the highest. The linoleic acid peroxidation inhibition activity of the prepared FPHs varied from 71 to 91%. The emulsion activity index of the FPHs prepared from catla and rohu decreased significantly with an increase in the DH (p < 0.05). The emulsion stability index of the FPHs prepared from the three species was the highest at 20% DH. FPHs prepared from freshwater carps possess good antioxidant and surface-active properties and are therefore suitable to be used as natural antioxidants in health-food formulation and as water-soluble antioxidants in the food-processing industry.     

Hydrolysis conditions for antioxidant peptides derived from enzymatic hydrolysates of sandfish (<Emphasis Type="Italic">Arctoscopus japonicus</Emphasis>)

Sandfish (Arctoscopus japonicus) meat and roe were used as natural materials for the preparation of antioxidant peptides using enzymatic hydrolysis. Meat and roe were hydrolyzed using Alcalase 2.4 L and Collupulin MG, respectively. Optimal hydrolysis conditions were determined through the effects of pH, temperature, enzyme concentration, and hydrolysis time on the radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH). The optimal hydrolysis conditions for meat hydrolysate (MHA) obtained via Alcalase 2.4 L treatment were a pH of 6.0, temperature of 70 °C, enzyme concentration of 5% (w/w), and a hydrolysis time of 3 h. The optimal hydrolysis conditions for roe hydrolysate (RHC) obtained via Collupulin MG treatment were pH 9.0, 60 °C temperature, 5% (w/w) enzyme concentration, and 1 h hydrolysis time. Under the optimal conditions, the DPPH radical scavenging activities of MHA and RHC were 60.04 and 79.65%, respectively. These results provide fundamental data for the production of antioxidant peptides derived from sandfish hydrolysates.     

Bioactive properties of Kilka (<Emphasis Type="Italic">Clupeonella cultriventris caspi</Emphasis>) fish protein hydrolysates

Whole common Kilka fish was hydrolyzed separately using four commercial enzymes, Alcalase, Neutrase, Protamex at 50 °C and Pepsin at 37 °C for 30, 60 and 90 min. Degree of hydrolysis, angiotensin-I-converting enzyme (ACE) inhibitory activity and antimicrobial activity of each hydrolysate against Gram-negative (Escherichia coli, Salmonella enteritidis) and Gram-positive (Staphylococcus aureus, Listeria innocua) bacteria were studied. Results showed that the degree of hydrolysis for all enzymes was in the range of 2.63–3.36%. Electrophoresis profiles of the Kilka protein hydrolysates showed that most of produced peptides were in the range of 30 D but Alcalase and Neutrase had a better performance in the production of low molecular weight peptides in the range of 10 D. This led to increase the antimicrobial activity against the examined bacteria at the concentration of 200 µg/mL peptide solution. The Neutrase enzyme produced hydrolysate with the highest ACE inhibitory activity (53%?±?1.8 at 500 µg/mL). Antimicrobial activity of Kilka protein hydrolysates using Protamex and Pepsin was lower than the others due to lack of considerable amount of small peptides. The current research has demonstrated that the peptides derived from the enzymatic hydrolysis of Kilka fish protein in optimum conditions are capable of being converted to antimicrobial and antihypertensive agents to be used in functional foods.     

Simultaneous Kinetic and Thermodynamic-Based Assay to Determine the Hydrogen Peroxide (H<Subscript>2</Subscript>O<Subscript>2</Subscript>) Scavenging Activity of Berry Extracts by Using Reaction Calorimetry

This work determines the radical scavenging activity of antioxidants and berry extracts based on the heat generated during their reaction with hydrogen peroxide, under isothermal condition (25 °C). After addition of H₂O₂ to a water solution containing antioxidants, an exothermic heat flow appeared. After an initial damping time, the signal decayed exponentially, following a first-order kinetic. Through an iterative fitting routine, both thermodynamic (ΔH) and kinetic (k) information were achieved. Such approach was applied toward relevant food antioxidants, revealing that the fastest reactivity (k) was for tannic acid > gallic acid > caffeic acid > ascorbic acid. Interestingly, k was inversely correlated with ΔH (r = ?0.96) and with the DPPH test (r = ?0.98). Apparently, strong radical scavengers show faster kinetics and lower ΔH-values, as expected, respectively, from a high reactivity toward peroxyl radical and efficient delocalization capacity. Such approach was finally applied to berry extracts (mixed grape seed and skin; chokeberries; grape seed; goji berries). The resulting ΔH-values were correlated with three indices, namely, total phenol, amperometry, and DPPH test. However, k-values largely deviated from these indices. Such discrepancy was explained considering that none of these indices is a “true” measure of the kinetic of the reaction, but only express an apparent concentration. Conversely, reaction calorimetry provides directly and simultaneously both thermodynamic and kinetic properties of the radical scavenging reactivity of antioxidants or natural extracts.     

Antioxidant Activity and Determination of Phenolic Compounds from <Emphasis Type="Italic">Eugenia involucrata</Emphasis> DC. Fruits by UHPLC-MS/MS

Fruits have been the focus of several studies aimed at finding new antioxidant sources for protection against the damage caused by reactive species. In this study, the antioxidant activity and the presence of phenolic compounds in all parts (peel, pulp, and seeds) of Eugenia involucrata DC. fruits were evaluated. DPPH^·, ABTS^·+, and ORAC methods were used to determine the antioxidant activity, and an UHPLC-MS/MS method was developed for determining the phenolic compounds (gallic, chlorogenic, ferulic, p-coumaric and ellagic acids, quercetin, and myricetin). In the determination of both antioxidant activity and phenolic composition, the efficiency of solvents with different polarities—methanol/H₂O (80:20, v/v), ethanol/H₂O (80:20, v/v), methanol/acidified water with phosphoric acid pH 3.00 (80:20, v/v), and ethyl acetate—for the extraction of the phenolic compounds, was also evaluated. All parts of E. involucrata fruits showed antioxidant activity, in the range of 36.68 ± 1.44 to 873.87 ± 18.24 μmol TE g^?1, being the highest values found in the seeds and peel when more polar extraction solvents were used. Six, five, and three phenolic compounds were identified and quantified in the pulp, peel, and seeds, respectively, with the highest abundance as p-coumaric acid (14 ± 2 mg kg^?1) in the pulp, quercetin (47 ± 5 mg kg^?1) in the peel, and gallic acid (74 ± 4 mg kg^?1) in the seeds, also when more polar solvents were used. Although antioxidant activity methods suggested that the peel and seeds have more antioxidant potential, a wider variety of compounds were determined in the pulp.     

Properties of a fibrinolytic enzyme secreted by <Emphasis Type="Italic">Bacillus subtilis</Emphasis> JS2 isolated from saeu (small shrimp) <Emphasis Type="Italic">jeotgal</Emphasis>

Bacillus species were screened to be used as starters for jeotgals, salted and fermented Korean sea foods. A strain, JS2, showing strong fibrinolytic activity was isolated from saeu (small shrimp) jeotgal, and identified as Bacillus subtilis. Bacillus subtilis JS2 grew well at 20% (w/v) NaCl concentration. SDS-PAGE of culture supernatant from JS2 showed 3 major bands of 27, 29, and 60 kDa in size. Fibrin zymography showed that the 27 kDa band was the major fibrinolytic protein. The gene, aprEJS2, was cloned and introduced into B. subtilis WB600 using pHY300PLK. A B. subtilis transformant harboring pHYJS2 showed higher fibrinolytic activity than B. subtilis JS2. aprEJS2 was overexpressed in Escherichia coli BL21 (DE3). The optimum pH and temperature for AprEJS2 were pH 8.0 and 40 °C, respectively. Km and V_max values were determined. AprEJS2 has strong α-fibrinogenase activity and moderate β-fibrinogenase activity.     

Study of Ca<Superscript>2+</Superscript>-ATPase Activity and Solubility in the Whole Kuruma Prawn (<Emphasis Type="Italic">Marsupenaeus japonicus</Emphasis>) Meat During Heating: Based on the Kinetics Analysis of Myofibril Protein Thermal Denaturation

Protein denaturation is considered to be the main cause of physicochemical changes in prawns during heating. However, no studies have been analyzed the kinetics of protein denaturation and the relationship between the degree of denaturation and chemical changes. Therefore, we investigated the changes in Ca²⁺-ATPase activity, protein solubility, and total sulfhydryl content of whole prawn meat during heating by determining the thermal denaturation kinetics of the proteins. Activation energies (E _a ) for the denaturation of myosin (183.2 kJ/mol) and actin (178.8 kJ/mol) were obtained by non-isothermal differential scanning calorimetry analysis. Using the kinetic parameters, the distribution of protein denaturation was predicted in whole prawns under arbitrary heating conditions. The results revealed an uneven distribution of the protein denaturation in prawns that was dependent on the heating conditions. Ca²⁺-ATPase activity decreased with increasing heating times at 51 or 85 °C and was strongly related to the average degree of protein denaturation. The results of protein solubility analysis suggested that hydrogen bonds, hydrophobic interactions, and ionic bonds changed with protein denaturation. The number of ionic bonds was reduced, while hydrogen content was enhanced at both temperatures. Hydrophobic interactions increased gradually at 51 °C (p?<?0.05). At 85 °C, hydrophobic interactions increased notably at first (p?<?0.05); however, as heating continued, no significant changes were observed (p?>?0.05). Our results indicate that the extent of protein solubility is significantly correlated with the average degree of protein denaturation during the heating process.     

Preparation and Release Behavior of Gelatin-Based Capsules of Antioxidants from Ethanolic Extracts of Thai Riceberry Bran

This study aimed to devise an environment-friendly and effective, yet simple and practicable, antioxidant extraction and encapsulation method from Riceberry bran, whose extract was used thereafter for developing highly efficient antioxidant capsules. Ethanolic Riceberry bran extracts with high total phenolic content, total flavonoid content, total anthocyanin content, and antioxidant activity (using DPPH radical scavenging activity and ferric reducing antioxidant power assay) were obtained using ultrasonic-assisted extraction. The optimum conditions for producing the capsules, such as types of gelatin, concentrations of gelatin, and the Riceberry bran extract concentrations, were studied. Capsules produced by incorporating 1% (w/v) of acid-treated gelatin (type A) and 1% (w/v) of Riceberry bran extract yielded higher chemical properties. When dispersed in water at 37 °C, the capsules exhibited a high release of antioxidants. Moreover, the capsule showed a lower degradation rate of antioxidants under simulated gastrointestinal conditions compared to the crude extract.     

Extraction and in vitro antioxidant capacity evaluation of phenolic compounds from pigmented aromatic rice (<Emphasis Type="Italic">Oryzae sativa</Emphasis> L.) cultivars

The aroma generating volatile components profile and in vitro antioxidant capacities of different aromatic rice cultivars was determined by GC–MS analysis and in terms of DPPH scavenging activity, lipid peroxidation inhibition, phosphomolybdenum reduction and reducing power assay. The total phenolic content including both free and bound forms in the analyzed aromatic rice cultivars, Mushki budgi (1.62 mg GAE/g), Mushki kandi (1.63 mg GAE/g) and Kamad (1.60 mg GAE/g) were found double the amount as compared to non-aromatic Koshkari (0.86 mg GAE/g) cultivar. The aromatic rice cultivars had also shown higher total flavonoid content and antioxidant activity than non-aromatic rice cultivar (Koshkari). The GC–MS results indicated 21-aromatic compounds present in sufficient quantities in aromatic cultivars and some of them were unique to these cultivars. Among the compounds identified, aldehydes were found in higher quantity followed by alkanes, ketones and esters. Among the aromatic rice cultivars, Mushki budgi and Mushki kandi were found possessing higher quantity of flavoring components such as benzaldehyde, a carcinostatic agent. The cultivars Mushki budgi and Mushki kandi indicated positive correlation of TPC, TFC and the in vitro antioxidant components largely, while the less aromatic Kamad, correlate with only two components viz DPPH and lipid peroxidation.     

Lipid oxidation-related characteristics of gim bugak (Korean fried cuisine with <Emphasis Type="Italic">Porphyra</Emphasis>) affected by frying oil

The effect of frying oil on the lipid oxidation, antioxidants, and in vitro antioxidant activity of gim bugak was studied. Bugak was prepared by pan-frying at 180 °C in unroasted sesame, soybean, extra virgin olive, or palm oil. The degree of lipid oxidation based on conjugated dienoic acid and p-anisidine values was higher in the bugak fried in soybean or sesame oil with high contents of polyunsaturated fatty acids and tocopherols. However, the oil oxidation was lower in olive and palm oils, which showed higher degradation of tocopherols and polyphenols than in sesame or soybean oil during frying. Although the bugak fried in palm oil contained less antioxidants than that fried in soybean or sesame oil, the in vitro antioxidant activity was not different (p > 0.05). Results suggest that palm oil can replace unroasted sesame oil for the preparation of gim bugak with improved lipid oxidative stability and health functionality.     

Design of Sonotrode Ultrasound-Assisted Extraction of Phenolic Compounds from <Emphasis Type="Italic">Psidium guajava</Emphasis> L. Leaves

Psidium guajava L. has gained a special attention as health plant due to the presence of phenolic compounds. Box-Behnken design (BBD) has been applied for the extraction of target compounds from guava leaves via sonotrode ultrasound-assisted extraction (UAE). Different extraction times (5, 30, and 55 min), ratios of ethanol/water (50, 75, and 100% (v/v)), and ultrasound (US) power (80, 240, and 400 W) were tested to find their effect on the sum of phenolic compound (SPC), flavonols and flavan-3-ols via HPLC-ESI-QqQ-MS, and antioxidant activity (DPPH and TEAC assays). The best process conditions were as follows: 40 min, 60% ethanol/water (v/v), and 200 W. Established method has been used to extract phenolic compounds in two guava leaves varieties (pyrifera and pomifera). Pyrifera var. showed greater values of the SPC via HPLC-ESI-QqQ-MS (49.7 mg/g leaf dry weight (d.w.)), flavonols (12.51 mg/g d.w.), flavan-3-ols (7.20 mg/g d.w.), individual phenolic compounds, and antioxidant activity (8970 ± 5 and 465 ± 6 μmol Trolox/g leaf d.w, respectively) than pomifera var. Conventional extraction showed lower amounts of phenolic compounds (7.81 ± 0.03 and 4.64 ± 0.01 mg/g leaf d.w. for flavonols and flavan-3ols, respectively) in comparison to the ultrasound-assisted ones.     

Development and characterization of reconstituted hydrogel from <Emphasis Type="Italic">Aloe vera</Emphasis> (<Emphasis Type="Italic">Aloe barbadensis</Emphasis> Miller) powder

Structural and rheological characterization of reconstituted hydrogels developed from A. vera non-fibrous alcohol insoluble residue (NFAIR) powder using different methods [viz., shaking (S), heating-shaking (HS), and heating (H)] and concentrations (viz., 0.2–1.6 %, w/v) was carried out. Functional group distribution by FTIR spectroscopy and Congo red (CR) method revealed the presence of acetylated acemannan in A. vera powder. Dynamic oscillation studies of A. vera (NFAIR) fluids at all concentrations of 0.2–1.6 %, w/v, showed gel strength in the order of H > HS > S method. However, in H method, increase in concentration from 0.2 to 1.6 %, w/v showed the conformational transition from semi-diluted solution to weak gel nature. Rheological models described the effect of heating temperatures (HT); 30–90 °C, and times (Ht); 15–60 min on viscoelastic behavior in reconstituted A. vera fluids. The reconstituted A. vera hydrogel prepared with a concentration of 1.6 %, w/v using 50 °C (HT) and 30 min (Ht) condition showed a good agreement with the Power law (storage modulus, G′) and Weak gel model (complex modulus, G*) fitted data (R² > 0.94) resulting higher viscoelastic moduli intercepts; G′₀ (71.5 Pa s ^n′), G″₀ (33.5 Pa s ^n″), lower slopes; n′ (0.22), n″ (0.06), higher network strength (A _F , 121.3 Pa s^1/z ) and number of network (z, 5.3) values. The obtained results suggested that heating at 50 °C/30 min can develop aqueous weak gel networks of A. vera with enhanced gel strength which may be utilized as a novel gelling agent for wide variety of targeted applications in food and pharmaceutical sectors.     

Modeling the Inactivation of <Emphasis Type="Italic">Listeria innocua</Emphasis> and <Emphasis Type="Italic">Escherichia coli</Emphasis> in Fresh-Cut Tomato Treated with Pulsed Light

The effectiveness of pulsed light (PL) treatments to inhibit microorganisms on fresh-cut tomatoes (Lycopersicon esculentum Mill., cv. Daniela) was investigated. Tomato slices inoculated with Escherichia coli or Listeria innocua were exposed to PL treatments (4, 6, or 8 J cm^?2 fluence) and kept cold at 4 °C for 20 days. L. innocua and E. coli counts, gases in the headspace of the containers (O₂ and CO₂), pH, titratable acidity, and soluble solid content were monitored throughout the cold storage. The PL treatments reduced significantly (p < 0.05) initial loads of both microbes. The effect of the PL fluence on the survival number of microoganisms was described by a log-linear model (R ² = 0.849–0.999). At any fixed time within the cold storing, the microbial counts for untreated samples were always higher than those cut tomatoes that had been previously PL-treated. The behavior of L. innocua and E. coli during the storage were well adjusted (R ² > 0.930) by Gompertzian models; the studied microorganisms exhibited different patterns during the storage period. On the other hand, O₂ and CO₂ partial pressures in containers with fresh-cut tomatoes were also significantly affected by PL treatments (p < 0.05). The highest PL fluence caused the greatest changes of O₂ and CO₂ contents. In addition, the application of PL triggered an acceleration of the O₂ consumption during the cold stage. PL treatments might be used to effectively extend the safety of fresh-cut tomatoes over 12 days of storage against E. coli and L. innocua growth.     

Chemical and nutritional properties of different fractions of <Emphasis Type="Italic">Prosopis alba</Emphasis> pods and seeds

The objective of this work was to study chemical and nutritional aspects of different fractions of Prosopis alba. Flours from whole pod, pericarp (pulp) and seeds were obtained. Polyphenols were mainly located in pulp but antioxidant activity was higher in whole pod flour and seeds. In seeds, the fraction with the highest polyphenols and antioxidant activity was the seed coat or testa. Protein content was higher in whole pod flour (5.81 %) than in pulp flour (3.52 %), presenting the seed an appreciable amount 33.6 %. These proteins were composed by monomer subunits of 85, 67, 38, 16 and 14 kDa and no prolamins and anti-tryptic activity were detected. P. alba flours presented high content of soluble sugars, mainly composed by sucrose, and also high amount of insoluble dietary fiber. The major mineral was potassium. The whole pod, due to the contribution of seeds, contained high amount of calcium, magnesium, iron and zinc, all indispensable minerals for human nutrition. Therefore, P. alba flours, mainly containing the seeds, constitute nutritional ingredients for bakery and gluten free products.     

Optimization of ultrasonic-assisted extraction of phenolic compounds from <Emphasis Type="Italic">Justicia spicigera</Emphasis> leaves

A Box–Behnken design (Extraction-time, pulse-cycle, sonication-amplitude) was employed to extract phenolic compounds from Justicia spicigera leaves by ultrasonic-assisted extraction. The muicle leaves extracts were analyzed measuring total phenolic compounds and antioxidant capacity. According to response surface methodology the optimal conditions of ultrasonic-assisted extraction to obtain the highest soluble phenolic content were 2 min (extraction time) for 0.7 s (pulse cycle) at 55% of sonication amplitude. Under these optimal conditions, the total phenolic content was higher when was used ultrasonic-assisted extraction (54.02 mg/g) than stirring (46.46 mg/g) and thermal decoction (47.76 mg/g); however, the antioxidant capacity from J. spicigera extracts did not increase by ultrasonic-assisted extraction. The extracts or aqueous infusions from J. spicigera leaves are used for therapeutic proposes, therefore the ultrasonic-assisted extraction is a useful technology to improve the extraction of phytochemicals from J. spicigera leaves.     

Effect of Solids Concentration on the Physicochemical and Flow Properties of Cactus Pear Juices of Two Varieties (<Emphasis Type="Italic">Opuntia ficus-indica</Emphasis> and <Emphasis Type="Italic">Opuntia streptacantha</Emphasis>)

Juices from two varieties of cactus pear, a green (Opuntia ficus-indica) and a red (Opuntia streptacantha), were obtained and concentrated by evaporation. Both fruit varieties and their juices at different concentrations were characterized. Green cactus pears had significantly higher amount of pulp than red cactus pears; the peel of O. ficus-indica represented only 38 versus 52 % of the fruit for the O. streptacantha. Both varieties had no significant differences on moisture, density, pH, and titratable acidity, in contrary to soluble solids. Juice was concentrated under vacuum conditions to reach a final concentration of 42, 53–55, and 58–60 °Brix, respectively, and stored under refrigeration (10 °C) during 4 weeks. Physicochemical properties of the pears and juices were determined as fresh items (time zero) and every week for the concentrate juices through storage; similarly, flow parameters were measured at 10 and 25 °C. Concentrate density (1160–1283 kg/m³) was mainly affected by final soluble solids, while pH and acidity were affected differently depending on the variety. Concentrated juices at 42 °Brix were considered with Newtonian behavior with a viscosity of 2–22 mPa s, while those at higher concentrations were of pseudoplastic nature (n < 1.0 and K > 69 mPa sⁿ). Power Law model fitted better the flow behavior than Herschel-Bulkley model of concentrates of both varieties. Temperature, solid concentration, and/or storage time affected the consistency coefficient (K) and flow index (n) depending on the cactus pear variety. Overall, those concentrated juices from O. streptacantha were more stable and exhibited lower apparent viscosity.     

Optimization of Extraction Parameters of Total Phenolics from <Emphasis Type="Italic">Annona crassiflora</Emphasis> Mart. (Araticum) Fruits Using Response Surface Methodology

In this study, response surface methodology was used to optimize the extraction temperature (25–75 °C) and ethanol concentration (0–70 %, ethanol/water, v/v) to maximize the extraction of total phenolic compounds (TPC) from araticum pulp. The efficiency of the extraction process was monitored over time, and equilibrium conditions were reached between 60–90 min. A second-order polynomial model was adequately fit to the experimental data with an adjusted R ² of 0.9793 (p < 0.0001) showing that the model could efficiently predict the TPC content. Optimum extraction conditions were ethanol concentration of 46 % (v/v), extraction temperature of 75 °C and extraction time of 90 min. Under the optimum conditions, the araticum pulp showed high TPC content (4.67 g GAE/100 g dw) and also high antioxidant activity in the different assays used (46.56 μg/mL, 683.65 μmol TE/g and 1593.72 μmol TE/g for DPPH IC₅₀, TEAC and T-ORAC_FL, respectively). From our extraction procedure, we successfully recovered a significantly higher amount of TPC compared to other studies in the literature to date (1.5–22-fold higher). Furthermore, TPC and antioxidant activity were present in the fruit in levels that are difficult to find in other common fruits. These results expose a potential approach for improving human health through consumption of araticum fruit.